Rotary shear valve assembly with a polymer insert device

ABSTRACT

A multi-position rotary shear valve assembly having a metallic or ceramic stator device and a metallic or ceramic rotor device. The stator device defines a planar stator face and two or more stator channels in fluid communication with the stator face at corresponding stator ports, while the rotor device includes a substantially planar rotor face defining one or more rotor channels. A tribological coating is disposed atop at least one of the rotor and stator face. The valve assembly includes a polymer insert device defining an exposed contact face having an inner diameter less than that of the outer circumferential edge and an outer diameter more than the outer circumferential edge. The insert device is formed for press-fit insertion in a groove defined in the rotor face. The outer circumferential edge of the stator face contacts the insert exposed face during rotation between the two or more rotor positions.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part application based upon patentapplication Ser. No. 12/833,834 (Attorney Docket No. RDYNP025), filedJul. 9, 2010, which in turn claims priority under 35 U.S.C. §119(e) fromco-pending U.S. Provisional Patent Application No. 61/225,143, filedJul. 13, 2009; 61/301,516, filed Feb. 4, 2010; and 61/328,594, filedApr. 27, 2010, all of which are entitled “ROTARY SHEAR VALVE ASSEMBLYWITH HARD-ON-HARD SEAL SURFACES”, all naming Tower as the inventor, andall of which are incorporated by reference in their entirety.

FIELD OF THE INVENTION

The present invention relates to rotary shear valves, and moreparticularly, relates to shear valves that incorporate hard-on-hardsealing surfaces.

BACKGROUND OF THE INVENTION

Current high pressure liquid chromatography shear valves typicallyemploy a metallic element and a rotor device composed of a polymermaterial that forms fluid-tight seal at a rotor/stator interface. Whilethis combination has been found to be successful, it is limited inpressure rating and valve lifetime. For example, applications requiringhigh pressures above 15 Kpsi and a lifetime greater than about 10Kcycles are not consistently attainable and sustainable using thiscombination.

Accordingly, it is desirable to provide a shear face valve capable ofholding pressures greater than about 15 Kpsi that have expected valvelifetimes greater than 50K cycles.

SUMMARY OF THE INVENTION

The present invention provides a rotary shear valve assembly including astator device that defines a substantially planar stator face and atleast two or more stator channels in fluid communication with statorface at corresponding stator ports. The valve assembly further includesa rotor device having a substantially hard, substantially planar rotorface defining one or more rotor channels. One of the stator face and therotor face terminates at an outer circumferential edge, and the other ofthe rotor face and the stator face extends radially beyond the outercircumferential edge of the one stator face and the rotor face when therotor device is rotatably mounted about a rotational axis to the statordevice. Such rotational mounting is in a manner enabling fluid-tight,selective relative rotation between the rotor face and the stator face,at a rotor-stator interface, between two or more rotor positions. Inaccordance with the present invention, the valve assembly includes apolymer insert device that defines an exposed contact face having aninsert inner diameter less than that of the outer circumferential edgeand an insert outer diameter more than the outer circumferential edge.The insert device is formed and dimensioned for press-fit insertion inan insert receiving groove defined in the other of the rotor face andthe stator face. The outer circumferential edge of the one of the statorface and the rotor face, thus, contacts the insert exposed face duringthe relative rotation between the two or more rotor positions.

In one specific embodiment, the insert exposed face is donut-shaped andsubstantially planar. Further, the receiving groove and the insertdevice cooperate to position the substantially planar insert exposedface substantially flush with the other of the substantially planarrotor face and the substantially planar stator face.

In another configuration, a groove inner diameter of the insertreceiving groove is in the range of about 0.001 inch to about 0.002 inchgreater than that of an insert inner diameter of the insert device.

In yet another specific embodiment, the polymer insert device iscomposed of a high compressive strength material, which includes anatural PAEK, a filled PAEK (or PEEK) or a polyimide material such asVESPEL®.

Still another configuration provides the stator face and the rotor faceas being composed substantially of one a metallic material and a ceramicmaterial.

The valve assembly further includes, in another embodiment, atribological coating disposed atop at least one of the rotor face andthe stator face. Such a coating, for instance, is a Diamond Like Carboncoating (DLC).

In yet another specific configuration, the valve assembly furtherincludes a compliance assembly cooperating with the rotor device in amanner orienting the substantially planar rotor face substantiallyparallel to and substantially flush against the substantially planarstator face of the stator device.

In another aspect of the present invention, a rotary shear valveassembly is provided having a stator boss device defining asubstantially hard, substantially planar stator face that terminates atan outer circumferential edge. A rotor device is further provided havinga substantially hard, substantially planar rotor face that is configuredto extend radially beyond the outer circumferential edge of the statorface when the rotor device is rotatably mounted about a rotational axisto the stator device. Such rotational mounting is in a manner enablingfluid-tight, selective relative rotation between the rotor face and thestator face, at a rotor-stator interface, between two or more rotorpositions. A tribological coating is disposed atop at least one of therotor face and the stator face. Further, the valve assembly includes apolymer insert device defining an exposed contact face having an insertinner diameter less than that of the outer circumferential edge and aninsert outer diameter more than the outer circumferential edge. Theinsert device is formed and dimensioned for press-fit insertion in areceiving groove defined in the rotor face such that the outercircumferential edge of the stator face contacts the insert exposed faceduring the relative rotation between the two or more rotor positions.

BRIEF DESCRIPTION OF THE DRAWINGS

The assembly of the present invention has other objects and features ofadvantage which will be more readily apparent from the followingdescription of the best mode of carrying out the invention and theappended claims, when taken in conjunction with the accompanyingdrawings, in which:

FIG. 1 is a top perspective view of a micro-fluidic valve assembly thatincorporates both a metallic rotor element and a metallic stator elementdesigned in accordance with the present invention.

FIG. 2 is a bottom perspective view of the micro-fluidic valve assemblyof FIG. 1.

FIG. 3 is a top perspective view of the micro-fluidic valve assembly ofFIG. 1, illustrating the rotor element with a stator ring and statorelement removed.

FIG. 4 is a side perspective view of the micro-fluidic valve assembly ofFIG. 1, illustrated with the stator ring removed.

FIG. 5 is an exploded, top perspective view of a rotor assembly and thestator element of the micro-fluidic valve assembly of FIG. 1.

FIG. 5 is an exploded, top perspective view of a rotor assembly and thestator element of the micro-fluidic valve assembly of FIG. 1.

FIG. 6 is an enlarged, top perspective view of the rotor assembly ofFIG. 5.

FIG. 7 is a partially exploded, top perspective view of the rotorassembly of FIG. 6, incorporating a compliance assembly constructed inaccordance with the present invention.

FIG. 8 is a reduced, exploded, bottom perspective view of themicro-fluidic valve assembly of FIG. 1.

FIG. 9 is a top perspective view of the rotor assembly incorporating analternative embodiment compliance assembly.

FIG. 10 is a partially exploded, top perspective view of the rotorassembly and compliance assembly of FIG. 9.

FIG. 11 is an exploded, top perspective view of the rotor assembly andcompliance assembly of FIG. 9, together with the stator element.

FIG. 12 is an exploded, bottom perspective view of the rotor assemblyand compliance assembly of FIG. 10.

FIG. 13 is an enlarged, fragmentary, side elevation view, incross-section, of the micro-fluidic valve assembly of FIG. 1,incorporating the compliance assembly of FIG. 9.

FIG. 14 is a side elevation view, in cross-section, of the complianceassembly of FIG. 13.

FIG. 15 is a top perspective view of the rotor assembly incorporatinganother alternative embodiment compliance assembly.

FIG. 16 is an exploded, top perspective view of the rotor assembly andcompliance assembly of FIG. 15.

FIG. 17 is an exploded, bottom perspective view of the rotor assemblyand compliance assembly of FIG. 15.

FIG. 18 is a side elevation view, in cross-section, of the rotorassembly and compliance assembly of FIG. 15.

FIG. 19 is a side elevation view, in cross-section, of the micro-fluidicvalve assembly of FIG. 1, incorporating the compliance assembly of FIG.15.

FIG. 20 is a partially exploded, side perspective view of the rotorassembly and compliance assembly of FIG. 15.

FIG. 21 is an exploded, bottom perspective view of the rotor assemblyand compliance assembly of FIG. 15.

FIG. 22 is an enlarged, exploded, bottom perspective view of thecompliance assembly of FIG. 15.

FIG. 23 is an enlarged, exploded, top perspective view of the complianceassembly of FIG. 15.

FIG. 24 is an enlarged, top plan view of the compliance assembly of FIG.15.

FIG. 25 is an enlarged, fragmentary, side elevation view, incross-section, of an alternative embodiment valve assembly incorporatinga polymer insert device in accordance with the present invention.

FIG. 26 is an exploded, top perspective view of the rotor device of FIG.25, illustrating the polymer insert device prior to insertion into areceiving groove.

FIG. 27 is a top perspective view of the rotor device of FIG. 25,illustrating the polymer insert device press-fit into the receivinggroove.

FIG. 28 is an enlarged top plan view of the of the rotor device of FIG.27.

FIG. 29 is a side elevation view, in cross-section, of the of the rotordevice of FIG. 28.

FIG. 30 is an enlarged, fragmentary, top perspective view of the rotordevice and insert device of FIG. 29.

FIG. 31 is a slightly exploded, enlarged, fragmentary, top perspectiveview of the rotor device and stator device of FIG. 25, showing the outercircumferential portion.

FIG. 32 is an enlarged, fragmentary, side elevation view, incross-section, of an alternative embodiment of the valve assembly ofFIG. 25, incorporating an alignment pin.

DETAILED DESCRIPTION OF THE INVENTION

While the present invention will be described with reference to a fewspecific embodiments, the description is illustrative of the inventionand is not to be construed as limiting the invention. Variousmodifications to the present invention can be made to the preferredembodiments by those skilled in the art without departing from the truespirit and scope of the invention as defined by the appended claims. Itwill be noted here that for a better understanding, like components aredesignated by like reference numerals throughout the various figures.

Referring now generally to FIGS. 1-8, a rotary shear valve assembly 20is provided that includes a stator device 21 having a substantiallymetallic or ceramic, substantially planar stator face 22. The statordevice defines at least two or more stator channels in fluidcommunication with stator face at corresponding stator ports 23. Thevalve assembly 20 further includes a rotor device 25 having asubstantially metallic or ceramic, substantially planar rotor face 26.In accordance with the present invention, a tribological coating isdisposed atop at least one of the rotor face and the stator face. Thus,when the rotor device 25 is rotatably mounted about a rotational axisfor selective relative rotation between the rotor face and the statorface, at a rotor-stator interface, a fluid-tight seal is formed betweenthe two metallic faces during relative rotation between two or morerotor positions.

Accordingly, due in part to the tribological coating, a metal-on-metalfluid-tight seal is formed at the rotor/stator interface for highpressure applications (i.e., 15 Kpsi to about 25 Kpsi) that is alsocapable of sustaining high lifecycle capacity (i.e., at least about 50Kcycles). Such a tribological coating on at least one of the rotor faceand/or stator face enables the formation of a durable fluid-tight andlow friction seal under the necessary high pressure compressivepressures between the stator device and the rotor device.

As will be described, at least the rotor face 26 and the stator face 22are both composed of a relatively rigid material for increaseddurability under high compression forces. In other configurations, theentire rotor device 25 and the stator device 21 is composed of asubstantially rigid material.

Preferably, both the rotor device and the stator device are comprised ofmetallic compositions such as 316 Stainless Steel, Duplex StainlessSteel, titanium, Alloy Steels or Tool Steel compositions. Other suitablerigid materials, however, have been found that yield similar highpressure ability together with a high lifecycle capacity can be applied,as long as a suitable tribological coating is disposed atop at least oneof the rotor face 26 and/or the stator face 22. One such suitablematerial family is ceramics, for instance, such as Alumina, SSIC,Zirconia. It will be appreciated, however, that whether the rotor andstator is composed of a metal or a ceramic material, that material mustbe capable of being coated with the tribological material.

Coating of at least one of the stator face and/or the rotor face hasbeen found necessary in these high pressure applications in order toform a fluid-tight, low friction seal at the rotor/stator interface. Dueto the substantially rigid material composition of the rotor face andthe stator face, for the aforementioned desired reasons, these rigidmaterials are of course relatively non-compliable.

Such a coating, however, must also exhibit sufficient structuralintegrity for a high lifecycle under these high fluid pressure, highcompressive force conditions. One such suitable and effective coatingfor pressurized fluid-tight seal formation between opposed rigid surfaceinterfaces, under these conditions, is the tribological coatings. Thesecoatings have been found to exhibit high strength (toughness) and lowfriction, as well as being resistant to most chemicals used in LiquidChromatography.

One specific tribological coating that is particularly suitable for thisapplication is the Diamond Like Carbon coatings (DLC), such as theBALINIT® DLC STAR and BALINIT® DLC provided by Balzers Oerlikon or the aDLC provided by Ionbond. Other tribological coatings that exhibit thesecharacteristics, however, can be applied.

In accordance with the present invention, at least one of, or both, thestator face and the rotor face 26 is coated with the tribologicalmaterial. In one specific embodiment, in certain conditions, applyingthe tribological coating to the stator face 22 of the stator boss 27 hasbeen found particularly advantageous to provide a stronger, longerlasting fluid-tight seal at the rotor-stator interface (FIG. 8). Forexample, for high fluid pressure applications (i.e., greater than about18 Kpsi, higher axial compression forces between the rotor face 26 andstator face 22 are necessary to maintain a fluid-tight seal. When thevalve is set (i.e., when the pressure adjuster nut is adjusted until arate of decay is achieved, typically this rate is 0.3 uL/min. Fluidpressure is applied to the valve through the stator port(s) rotor sealgroove(s). Once the valve holds the required amount of pressure (15-25Kpsi in this instance) at the 0.3 uL/min leak rate, the valve is “set”.The high pressure applied to the seal by a spring assembly 30 (thatincludes an adjuster nut 31 and spring washers 32 (FIG. 8)) occasionallycauses the coating seal to be indented by the circumferential edgeportion of the stator boss 27. Thus, if the rotor face 26 is coated(e.g., the rotor face alone or in combination with the stator face),inconsistent results and damage components have been observed in theseinstances due to cracking of the coating, or delaminating at the edgeportion as the valve is actuated.

It is believed that this indentation causes the coating to “flake-off”or delaminate from the rotor seal in the area of the indentation as thevalve is actuated. As this coating is removed, the debris, and possiblythe uncoated metal, has been observed to score the remaining coating,degrading the integrity of the coating on the stator boss, and causingthe coating on the stator to fail. Once this degradation commences, thefluid-tight seal at the rotor/stator interface will fail in holdingpressure.

When only the stator face is coated with the tribological coating, underthese high pressure applications, this degradation is not observed. Itwill further be noted that at lower pressures (3-6 Kpsi), it is believedthat both the stator and rotor seal could be coated (DLC or otherwise)and provide a good seal, since hard-on-hard valves work at thesepressures. Since these pressures applied to the seal would be lower, therotor seal is less likely to be indented and cause the coating to fail.

Referring now to FIGS. 1-5 and 8, a typical shear valve assembly 20 isshown and described. Briefly, as best illustrated in FIG. 8, the shearvalve assembly typically includes a housing assembly 33 (essentiallycomprised of a valve housing and a stator ring) upon which a rotorassembly 29 is rotatably disposed therein. The rotor assembly 29includes a drive shaft 35 and a distally disposed head assembly 36 thatis configured to seat the rotor device 25 thereon. To promote forceconcentration and the ability of the rotor device to pivot atop the headassembly 36, the head assembly includes a raised platform or pad 34upstanding slightly from a distal surface 38 thereof. This upstandingshaft pad 34 is preferably disk-shaped, having a substantially planarseating surface 39 that is configured to seat directly against a contactsurface 40 of the rotor device 25. It will be appreciated, however, thatFIGS. 5, 7 and 8 are illustrated with a thin compliant element or shimmember 44 disposed there between which will be described in detailbelow.

The diameter of this upstanding pad 34 is preferably less than that ofthe contact surface 40 of the rotor device. However, the diameter isalso preferably not less than a range of about 45% that of the rotordevice, such that the smaller diameter allows minute teetering of therotor device so that the rotor face and stator face will be in fullcontact therebetween. Accordingly, as will be described in greaterdetail below, the contact surface 40 of the rotor device 25 and seatingsurface 39 of the upstanding shaft pad 34 need not be in substantiallyflush contact with one another. In one specific embodiment, the diameterof the upstanding pad may be in the range of about 0.200″ to about0.368″, and more preferably about 0.230″, while the diameter of therotor device may be in the range of about 0.600″ to about 0.625″.

In a typical configuration, three strategically oriented dowel pins 37extend distally from the distal surface 38 of the head assembly 36(FIGS. 5-7). These dowel pins 37 are slideably received in correspondingthrough-holes 41 in the disk-shaped rotor device 25 that function tomount and align the rotor device 25 relative to the drive shaft 35.Furthermore, these dowel pins 37 enable torque transfer, and thus,rotation of the rotor device 25 as the drive shaft 35 is rotated aboutthe rotational axis.

The stator device 21 is mounted to a distal portion 42 of the housingassembly 33, via nuts 43, in a manner positioning the stator face 22 ofthe stator boss adjacent to and in contact with the rotor face 26 of therotor device 25. To generate the compressive force between the rotordevice 25 and the stator device 21, at the rotor-stator interface, thespring assembly 30 is cooperates between the housing assembly 33 and thehead assembly of the drive shaft 35. Briefly, a pressure adjuster nut 31is threadably mounted to the proximal portion of the housing assembly33. As the distal end of the pressure adjuster nut compresses a springstack (i.e., the stack of spring washers 32) against the head assembly36 the rotor device 25 is compressively urged against the stator boss27. Newer micro-fluidic valves have recently been developed thatincorporate pressure adjuster assemblies for ultra-high pressure fluidapplications that offer significant valve rebuild advantages. Theseassemblies are disclosed in our U.S. patent application Ser. No.12/815,265 to Tower et al, filed Jun. 14, 2010, entitled “REBUILDABLEMICRO-FLUIDIC VALVE ASSEMBLY”, which is incorporated by reference in itsentirety.

Referring now to FIGS. 3-7, and in accordance with the presentinvention, both the stator device 21 and the rotor device 25 arecomposed of a metallic material, forming a metal-on-metal stator-rotorinterface. The tribological coating (preferably a DLC) isolates truemetal-to-metal contact, of course, functioning to form a fluid-tightseal under higher pressure situations. As indicated above, forapplications greater than about 15 Kpsi, the stator face 22 ispreferably coated, while for applications ranging from about 3 Kpsi toless than about 6 Kpsi, either the stator face 22, the rotor face 26 orboth faces can be coated.

In this coated, metal-on-metal configuration, due to the rigidity andhardness of these shear face valve components, it is highly beneficialto orient the substantially planar faces of the stator device and therotor device substantially parallel to one another. However, while suchsubstantially parallel orientation is attainable, this may be costprohibitive, and thus not be practical. Due to the collective stack upof component tolerances, the metal rotor face 26 may not seal flatly orsubstantially parallel and flush to the substantially planar statorface, or the stator may not be perfectly planar in the first place.

Therefore, in accordance with another aspect of the present invention,the rotor assembly 29 incorporates a rotor face compliance assembly 45that cooperates with the substantially planar rotor face 26 to orient itsubstantially parallel to the stator face 22. The compliance assembly45, for example, includes a compliant element (e.g., a shim member 44 ofthe embodiment of FIGS. 5-8, or a support device 50 of the embodiment ofFIGS. 9-13) disposed between the head assembly 36 and the rotor device25 (or at least metallic or ceramic portion thereof, such as the rotorelement 46 of the embodiment of FIGS. 9-13) that is compressible in amanner enabling the substantially planar rotor face 26 to orientsubstantially parallel to the stator face 22. In one particularembodiment, as above-mentioned, the compliant element is provided by acompliant shim member 44 disposed between the distal seating surface 39of the raised platform 34 and the contact surface 40 of the rotorassembly 29. Hence, upon compression of the head assembly 36 against therotor device 25, and thus, compression of the rotor face against thestator face, the substantially more compliant shim 44 will be caused tocompress in a manner that seats the rotor face more flush and parallelagainst stator face. As mentioned above, thus, the need for a completelyflush seat between the contact surface 40 of the rotor device 25 and theseating surface 39 of the upstanding shaft pad 34 is not as necessary toensure a flush, sealed contact between the rotor face and the statorface.

The diameter of the shim member 44 is preferably less than that of thecontact surface 40 of the rotor device 25, but must incorporatethrough-holes 48 that are strategically aligned to receive and cooperatewith the dowel pins 37 that extend distally from the distal surface 38of the head assembly 36 (FIGS. 5-7). Similar to the rotor device 25,these dowel pins 37 are slideably received in the correspondingthrough-holes 48 in the shim 44 to mount, secure and align the shim 44relative to the head assembly 36.

As best shown in FIGS. 5, 7 and 8, the shim may be comprised of manydifferent shapes. For instance, the shim may be a conventional circularshape (FIG. 8), or may be an efficient, minute triangular shape (FIGS. 5and 7).

The material composition of the shim 44 should have sufficientstructural integrity to withstand the substantial compressive forcesapplied between the rotor device and the stator device. However, thematerial must also be sufficiently compliable to enable the rotor faceto seat substantially flush against the stator face, during operativecompression. The compressive modulus, k, for instance, is preferably inthe range of about 250 to about 300 kpsi. In one particular embodiment,the material composition of the shim 44 may be comprised of PolyethyleneTerephthalete Glycol (PETG), Polyester or Polycarbonate, having athickness in the range of about 0.010″ to about 0.040″.

In another specific embodiment of the compliance assembly 45, asillustrated in FIGS. 9-12, the rotor device 25 is comprised of ametallic or ceramic (insertable) rotor element 46 that is received andsupported by a compliant support device 50. In this embodiment, thesupport device 50 functions as the compliant element, and thus, providesa compliant backing against the back side (i.e., the proximal face) ofthe inserted rotor element 46. FIGS. 10-12 best illustrate that themetallic rotor element 46 is preferably disk-shaped having the distalfacing, substantially planar rotor face 26 containing the rotor channels47.

The support device 50 is for the most part is shaped similar to atypical rotor device 25, such as that in the embodiment of FIGS. 5-7.The distal face of the support device, however, defines a receivingsocket 51 with a peripheral interior sidewall 52 formed and dimensionedfor press-fit receipt of the outer circumferential or peripheral wall 53of the rotor element 46 until a proximal face 54 thereof contacts and issupported by the distal socket face 55 of the receiving socket 51.

By providing a compliant backing material, at least in the axialdirection, upon the application of a compressive force between the rotordevice 25 and the stator face 22, the contacting surfaces of the supportdevice 50 should have some compliance or compression. Such compressivecompliance allows the substantially planar rotor face 26 to slightlyrelocate to an orientation that is substantially parallel to thesubstantially planar stator face. In other words, the compliant materialwill “move” or compress, due to contact with the backside contactsurface of the metal rotor element, allowing the polymer to absorb anymisalignment between the rotor face and the stator face of the statorboss. The rotor face 26 can then seal and mate flat against andsubstantially parallel to the stator boss face 22.

In one specific embodiment, the support device 50 is preferably about0.100″ to about 0.200″ thick, has a compressive modulus, k, in the rangeof about 4000 to about 5000 kpsi, and is composed of a polymer materialexhibiting high tensile and compressive strength. Such a compliantmaterial exhibiting these other properties, permits minute compliance,while further permitting transfer of the high compressive forces in theaxial direction to the rotor face 26 of the rotor element 46. As bestillustrated in FIGS. 13 and 14, compliance on the order of about 1° orabout 0.005″ at the circumferential edges of the rotor element isattainable.

The polymer material used can be changed for a variety of applications.Depending upon whether the application is for the lower region of whatis considered a high lower pressure application (e.g., 3-6 Kpsi), asofter unfilled polymer, such as PEEK™ or Nylon, may be applied. Incontrast, for higher pressure applications (e.g., 15-25 Kpsi), a carbonfilled polymer material may be necessary which significantly increasesthe polymers tensile and compressive strength.

One such high strength polymer support material is an engineered blendof PEEK™ with carbon fibers (e.g., a 20%-30% carbon PEEK™ blend). Thispolymer material is carbon filled, yielding the requisite high tensileand compressive strength. Thus, due to the high pressures of the springwashers 32 needed to seal the valve, this PEEK™ blend is currently thepreferred material. It will be appreciated, however, that other polymerbased materials, or even a higher strength elastomer could be used.

Turning now to FIGS. 10 and 11, the disk-shaped rotor element 46 isgenerally keyed. Not only does this aligned the rotor face 26 relativeto the drive shaft 35, but also functions to facilitate torque transferto the rotor element during the rotation of the support device 50. Forease of machining, the rotor element 46 is “D” shaped and the femalereceiving socket 51 is a modified “D” shape where the corners of theflat have been relieved for the radius of an end mill. The two parts areassembled by using an arbor press. The arbor press press-fits (0.002″press fit) the two parts together. It will be appreciated, of course,that the outer peripheral edges may be any shape that enables the metalseal insert to press-fit into the polymer backing.

Referring now the embodiment of FIGS. 16-24, the rotor assembly 29incorporates an alternative embodiment rotor face compliance assembly 45that enables the rotor face to “rock” and/or “pivot” to an orientationthat allows the opposed rotor face and stator face to seal and mateflushly against one another on the stator boss 27.

In this configuration, in a simplified description, a disk-shapedmetallic rotor element 60 (similar to that provided the embodiment ofFIGS. 16 and 20-23) is pivotally seated atop a ball bearing 61, which inturn, is seated atop a distal end of the head assembly 36 of the driveshaft 35. Accordingly, as a compressive force is applied to the driveshaft 35, the force is transferred, via the ball bearing 61, to therotor element 60. Upon increasing pressure between the adjacent, andopposed contact, at the rotor/stator interface, the rotor element 60 iscaused to minutely rock or pivot in an effort to reorient and align therotor face substantially parallel to the stator face.

To facilitate support of the pivoting rotor element 60, a drive ring 62is provided that is also shaped similar to the conventional rotor deviceit replaces. FIGS. 16 and 17 best illustrate that this drive ringincludes an axially extending receiving aperture 63 formed for axialreceipt of the rotor element 60 in a manner allowing the insert to“float” axially therein, while at the same time securing the rotorelement rotationally to the drive ring 62 for rotation about therotational axis.

Accordingly, the inner diameter of the inner sidewall 66 that definesthe receiving aperture 63 is slightly larger than the diameter of theouter circumferential wall 67 of the rotor element 60 to permit minutepivotal movement thereof. The clearance, for example, between the outerdiameter of the seal insert and the inner diameter of the drive ring isabout 0.020″ (0.010″per side). This allows the seal insert to movelaterally back and forth within the ring drive 0.010″ per side.

To provide seating support atop the ball bearing 61, the proximal facingsurface of the rotor element 60 includes a dome-shaped ball socket 68that is formed, sized and dimensioned to receive a portion of the ballbearing. This configuration is further responsible for providing thepivotal support about ball bearing, and relative to the drive ring 62.

To transfer torque to the axially free floating rotor element 60, as thedrive ring 62 rotates about the drive shaft axis, a plurality of guidepins 70 extend radially into the aperture 63 from the inner sidewall 66of the drive ring 62. These radial guide pins 70 are formed for slidingaxial receipt in corresponding elongated receiving slots 71 extending inan axial direction along the outer circumferential wall 67 of the rotorelement. Accordingly, as the drive ring is rotated, the guide pins 70transfer this rotational motion directly to the rotor element.

For precise and accurate rotational displacement and movement of therotor element, the tolerances between the diameter of the guide pins 70and the width of the corresponding receiving slots should therefore berelatively small. In one specific embodiment, for example, the tolerancebetween the diameter of guide pins and the width of the slots isapproximately 0.002″ (0.001″ per side). For instance, if the diameter ofthe guide pin is selected to be about 0.029″-0.031″, then the width ofthe guide slot 71 in the rotor element should be selected to be in therange of about seal is 0.031″-0.033″. Such a relatively small tolerancewill enable substantially immediate transfer of the rotation of thedrive ring 62, about the drive shaft axis, directly to the rotor element60. The relative position of the rotor seal grooves 47 relative to thestator ports 23 can therefore be accurately determined.

These radially spaced guide slots 71, however, also extend radially intothe outer circumferential wall 67 of the rotor element by a depthslightly greater than the radial length of the guide pins 70. Thistolerance permits guide pins 70 to extend slightly into and out of thecorresponding guide slots to enable the aforementioned minute lateralmovement (on the order of about 0.010″ per side) of the rotor devicewithin the drive ring receiving aperture 63. Hence, as the rotor element60 minutely pivots or rolls about the ball bearing, it also slides alongthe guide pins 70. This relative axial movement (as well as very minute,relative radial movement) of the guide pins 70 axially along thecorresponding receiving slots 71, while also moving minutely laterallywithin the receiving aperture, enabling the substantially planar rotorface 26 to slightly reorient substantially parallel to the stator face22. Thus, unlike the polymer backed support device 50 of the embodimentsof FIGS. 18-21, the compliance from this pivotal embodiment is providedby the ability of the rotor element seal insert to “move” and “pivot”(i.e., roll) about the ball bearing until the rotor face is reorientedsubstantially parallel to, and substantially flat against the statorface 22 of the stator boss 27.

These guide pins 70 can be provided by threaded screws (as shown andillustrated) or can be molded or milled during formation of the drivering 62. Moreover, while five guide pins 70 are shown radially spacedabout the inner sidewall 66 of the receiving aperture 63, the complianceassembly 45 could function with only one guide pin and correspondingslot (albeit a more limited compliance). A minimum of three radiallyspaced guide pins and corresponding guide slots, however, are desired toprovide an increased scope of compliance.

An opposed domed-shape socket 72 is also defined by the distal face ofthe head assembly 36 that is formed to similarly seat against the ballbearing 61. Preferably, this opposed domed-shape socket 72 is providedby an insertable dowel pin 73, press-fit into a corresponding passage 75at the distal end of the drive shaft 35.

Referring now to FIGS. 18 and 19, as a compression force, via springassembly 30, axially urges the drive shaft 35 toward the stator device21, the dowel pin 73 compresses the ball bearing 61. In turn, the ballbearing 61 transfers this axial compressive force to the rotor element60 to form the fluid-tight seal at the rotor-stator interface.

It will be appreciated that, in order to accommodate the highcompressive forces applied to the ball bearing, the diameter of the ballbearing should be at least about ½ (and preferably ⅔) the diameter ofthe rotor element 60. This assures that the compressive forces will bemore widely distributed about the domed-shaped socket 68 of the rotorelement, as compared to a more concentrated force distribution shouldthe ball bearing be of a smaller diameter.

Through many trials of testing of tribological coatings, especially DLCcoatings, under ultra high pressure (UHP) applications (e.g., 20 kpsi orhigher), for the above-mentioned hard-on-hard rotary valves (e.g.,metal-on-metal or ceramic-on-metal valves), increased wear has beenobserved in the tribological coatings, in certain contact regions, thatpromote premature valve failure. In one example, as best viewed in FIGS.25 and 31, a main region where excessive wear in the tribologicalcoating has been observed is at the outer circumferential portion 80(particularly an outer circumferential edge 81) of the stator boss 27.This outer portion is exposed to extremely high stress and the highestvelocity of the rotor seal during switching of the valve.

Consequently, cracking, flaking or delaminating of the tribologicalcoating have been observed whereupon the removed debris, and possiblythe uncoated metal, is believed to score the remaining coating, therebydegrading the integrity of the coating on the stator boss, and causingthe coating on the stator to fail. Again, once this degradationcommences, the fluid-tight seal at the rotor/stator interface will failin holding pressure.

In accordance with another aspect of the present invention and as bestshown in FIGS. 25-31, a rotary shear valve assembly, generallydesignated 20, has been developed that includes a stator device 21 and arotor device 25. The stator device 21 defines a substantially hard,substantially planar stator face 22 and at least two or more statorchannels 82 in fluid communication with the stator face 22 atcorresponding stator ports, while the rotor device 25 defines asubstantially hard, substantially planar rotor face 26 defining one ormore rotor channels 47. One of the stator face 22 and the rotor face 26terminates at an outer circumferential edge 81 (e.g., the stator face 22in particular embodiment of FIGS. 25 and 31), and the other of the rotorface 26 and the stator face 22 extends radially beyond the outercircumferential edge 81 of the one stator face 22 and the rotor face 26when the rotor device 25 is rotatably mounted about a rotational axis tothe stator device 21. Such rotational mounting cooperates in a mannerenabling fluid-tight, selective relative rotation between the rotor face26 and the stator face 22, at a rotor-stator interface, between two ormore rotor positions. In accordance with the present invention, thevalve assembly 20 includes a polymer insert device, generally designated83, that is formed and dimensioned for press-fit insertion into areceiving groove 85 defined in the other of the rotor face 26 and thestator face 22 (e.g., the rotor face 26 in FIGS. 26 and 27) such thatthe outer circumferential edge 81 of the one of the stator face 22 andthe rotor face 26 (e.g., the stator face 22 in FIGS. 25 and 31) contactsthe insert device 83 during the relative rotation between the two ormore rotor positions. The insert device 83, in particular, defines anexposed contact face 86 that has an insert inner diameter less than thatof the outer circumferential edge 81 (e.g., the stator face 22 in FIG.31), and an insert outer diameter that is greater than that of the outercircumferential edge.

Accordingly, the hard-on-hard (e.g., metal-on-metal or metal-on-ceramic)contact between the rotor face 26 and the stator face 22, at thecircumferential edge 81, is essentially supplanted with contact betweenthe polymer insert device 83 and the hard circumferential edge. Therotating contact between the metallic and/or ceramic circumferentialedge 81 with the exposed contact face 86 of the polymer insert device,at this outer circumferential portion 80, enables fluid-tight contactwith the circumferential edge 81, as well as providing sufficientdeformation to substantially absorb the high stress generated thereat.Since the tribological coating in this outer circumferential portion 80,particularly at the outer circumferential edge 81, is now exposed tosignificantly lower stresses, wear, scoring and/or chipping of thetribological coating is also significantly reduced.

Due to the rotating contact between the stator face 22 and the exposedcontact face 86 of the insert device, one important material property ofthe insert device 83 is that the selected polymer performs well in abearing application under UHP applications. Moreover, while the selectedpolymer material of the insert device must exhibit high compressivestrength, its modulus of elasticity of about 1193 kpsi and a compressivemodulus of about 68.4 kpsi, it must be significantly less than that fora ceramic or metallic material of the stator face and/or rotor face.This, of course, allows the polymer insert device 83 to locally absorbthe high stresses at these regions. Examples of such suitable polymermaterials include natural Polyaryletherketone (PAEK), filled PAEK (e.g.,PEEK®) or a polyimide material such as VESPEL®.

Briefly, while this aspect of the present invention is illustrated andthus described with the outer circumferential edge 81 oriented alongeither of the stator face 22 or the rotor face 26 (e.g., the stator face22 in FIGS. 25 and 31), and the other of the rotor face 26 or the statorface 22 supports the opposed insert device 83 thereof, for the ease ofdescription, all reference henceforth relates to placement of the insertdevice 83 with the rotor face 26. Moreover, it will be appreciated thatFIG. 31 illustrates the stator device 21 and the rotor device 25minutely displaced from one another for the ease of illustration. Duringoperation of the valve assembly 20, the rotor face 26 would be inrotating contact with the stator face 22.

As indicated above, in this particular embodiment, the stator device 21of the valve assembly 20 incorporates a down-standing stator boss 27.This boss is defined in part by an annular outer circumferential sidewall 87 that tapers inwardly, forming a conical-shaped chamfer. Thisconical side wall 87 intersects the stator face 22, forming the outercircumferential edge 81, in this embodiment.

Positioned in opposed contacting relationship to the outercircumferential portion 80 is the polymer insert device 83. This insertdevice is preferably ring-shaped (FIGS. 26-29), having a substantiallyplanar exposed contact face 86, and configured to be press-fit disposedin a substantially similarly annular recess or receiving groove 85,defined in the substantially planar rotor face 26. This receiving grooveis sized an dimensioned to cooperate with the insert device to fixedlyretain the insert to the rotor device 25, during valve operation, and toposition the exposed contact face 86 of the polymer insert device 83substantially flush with that of the substantially planar rotor face 26when in compressive contact against the stator face 22.

To assure contact and alignment of the stator circumferential edge 81with the contact face 86 of the insert device 83, the groove innerdiametric edge 89 of the annular groove 85 is sufficiently spacedradially inwardly from anticipated line of contact between the insertdevice and the stator outer circumferential edge 81. The radial positionof the groove inner diametric edge, however, must sufficiently spacedfrom an outer edge 88 of the rotor channel 47 so as to enable theformation of a fluid-tight seal is between the stator face 22 and therotor face under the aforementioned operating conditions (i.e., ultrahigh pressure, such as 20 kpsi or higher, hard-on-hard applications). Inother words, the minimum outer radial depth, L₁, between the rotorchannel outer edge 88 and the groove inner diametric edge 89 must besufficient for fluid-tight seal formation. In one specific embodiment,as best illustrated in FIGS. 30 and 31, the minimum outer radial depth,L₁, between the rotor channel outer edge 88 and the groove innerdiametric edge 89 should be at least about as wide as the width, W_(C),of the transverse cross section dimension of the rotor channel 47.

On the other hand, it will be appreciated that the minimum interiorradial depth, L₂, between the groove inner diametric edge 89 and theregion of contact with the stator outer circumferential edge 81 to be atleast about two times the rotor channel width, W_(C). Such a minimuminterior radial depth, L₂, will assure rotational bearing contact of thestator outer circumferential edge 81 with the exposed contact face 86 ofthe insert device 83.

Similarly, the groove outer diametric edge 90 is also sufficientlyspaced radially outward from the outer circumferential portion 80,particularly, the stator circumferential edge 81, to assure contacttherebetween. As best shown in FIG. 31, the minimum outer radial depth,L₃, between the region of contact with the stator outer circumferentialedge 81 and the groove outer diametric edge 90 is preferably at leastabout as long as the hypotenuse of the chamfer (i.e., the stator bossside wall 87).

The polymer insert device 83, as mentioned above, cooperates with thereceiving groove 85 for press-fit receipt therein. Hence, the outershell of the insert device 83 and the interior walls defining thereceiving groove 85 are similarly shaped, formed and dimensioned,with-in predetermined tolerances. The press fit nature of the insertaround the inner diametric wall 91 should therefore be sufficient tofixedly retain the insert within the receiving groove 85 duringoperation of the valve assembly, while at the same time, not be so snugas to jeopardize the structural integrity of the insert device 83. Inone particular embodiment, for instance, a diameter of the innerdiametric wall 91 of the receiving groove 85 is on the order of about0.001-0.002″ greater than that of the inner wall 92 of the insert device83 which, when press-fit over the groove inner diametric wall, will beadequate to affix the polymer insert in place during valve operationunder UHP applications.

By comparison, however, the polymer insert device 83 and the annularreceiving groove 85 are machined such that the groove outer diameter isactually slightly larger than that of the outer diameter of the insertdevice. This tolerance allows the polymer insert device 83 to expandradially outward while under load. By way of example, the diameter ofouter diametric wall 93 of the receiving groove 85 is in the range ofabout 0.005″ to about 0.020″ larger than that of the outer wall 95 ofthe insert device, and more preferably in the range of about 0.010″larger.

Accordingly, in one specific embodiment just described, the insert innerwall 92 and the groove inner diametric wall 91 interface cooperate in apress-fit manner, while the insert outer wall 95 and the groove outerdiametric wall 93 interface cooperate in an expansive manner. It will beappreciated, however, that the insert outer wall 95 and the groove outerdiametric wall 93 interface cooperate in the above-mentioned press-fitmanner, while the insert inner wall 92 and the groove inner diametricwall 91 interface cooperate in above-mentioned expansive manner. In yetanother configuration, both the inner and outer interfaces can beconfigured to cooperate in a press-fit manner.

The minimum depth of the polymer insert device is selected to be in therange of about 0.050″ to a maximum depth in the range of about 0.140″,and is more preferably about 0.050″″. This depth of the polymer insertshould be sufficient to extend slightly above the rotor face at leastinitially, as will be described below.

During fabrication and assembly, the initial height of the insert device83, however, is selected to be slightly taller than that of thereceiving groove 85 so that the exposed contact face 86 is slightlyraised above the substantially planar rotor face 26 when the insertdevice 83 is fully received and inserted therein. Once the insert device83 has been press-fit around the groove inner diametric wall 91 and intothe receiving groove 85 of the rotor device 25, a lapping and polishingprocess is performed on the rotor seal to procure a very shiny, smooth,substantially planar surface of the rotor face. This procedure ensuresthat the rotor face 26 and the polymer contact face 86 are substantiallyplanar and substantially flush with one another. After thislapping/polishing procedure, the rotor seal is cleaned and is ready tobe assembled into the valve assembly.

Applying the above-mentioned parameters, by way of example and in oneparticular embodiment, the inner diameter of the insert device is about0.128″ to about 0.129″ while the outer diameter thereof is about 0.225″.By comparison, the inner diameter of the receiving groove is about0.130″ while the outer diameter thereof is about 0.235″.

As best viewed in FIG. 32, the valve assembly 20 may incorporate analignment pin 96 that facilitates precise alignment between rotor device25 and the stator device 21, as well as relative to the head assembly36. This alignment pin 96 upstands axially from the shaft pad 34, and isformed for sliding receipt through an alignment aperture 97 extendingaxially through the rotor device 25. Axially aligned with the rotoralignment aperture 97 is a stator alignment slot 98.

Accordingly, upon assembly of the rotor device 25 and the stator device21 about the alignment pin 96, the rotor face 26 and the stator face 22are easily aligned, properly aligning the stator outer circumferentialedge 81 with the exposed contact face 86.

Furthermore, while the present invention has been described inconnection with the preferred form of practicing it and modificationsthereto, those of ordinary skill in the art will understand that manyother modifications can be made thereto within the scope of the claimsthat follow. Accordingly, it is not intended that the scope of theinvention in any way be limited by the above description, but instead bedetermined entirely by reference to the claims that follow. For example,while the present invention is particularly suitable for hard-on-hardUHP applications, it may also be applied in other lower pressurehard-on-hard applications as a means to increase the valve life time.

1. A rotary shear valve assembly comprising: a stator device defining asubstantially hard, substantially planar stator face and at least two ormore stator channels in fluid communication with said stator face atcorresponding stator ports; a rotor device having a substantially hard,substantially planar rotor face defining one or more rotor channels; oneof the stator face and the rotor face terminating at an outercircumferential edge, and the other of the rotor face and the statorface extending radially beyond the outer circumferential edge of the onestator face and the rotor face when said rotor device is rotatablymounted about a rotational axis to the stator device in a mannerenabling fluid-tight, selective relative rotation between the rotor faceand the stator face, at a rotor-stator interface, between two or morerotor positions; and a polymer insert device defining an exposed contactface having an insert inner diameter less than that of said outercircumferential edge and an insert outer diameter more than said outercircumferential edge, said insert device being formed and dimensionedfor press-fit insertion in a receiving groove defined in the other ofthe rotor face and the stator face such that the outer circumferentialedge of the one of the stator face and the rotor face contacts theinsert exposed face during said relative rotation between said two ormore rotor positions.
 2. The valve assembly according to claim 1,wherein said insert exposed face is donut-shaped and substantiallyplanar.
 3. The valve assembly according to claim 2, wherein saidreceiving groove and said insert device cooperate to position thesubstantially planar insert exposed face substantially flush with saidother of the substantially planar rotor face and the substantiallyplanar stator face.
 4. The valve assembly according to claim 2, whereina groove inner diameter of the insert receiving groove is in the rangeof about 0.001 inch to about 0.002 inch greater than an insert innerdiameter of the insert device, and a groove outer diameter of the insertreceiving groove is in the range of about 0.005 inch to about 0.020 inchgreater than an insert outer diameter of the insert device.
 5. The valveassembly according to claim 1, wherein said polymer insert device iscomposed of a high compressive strength material.
 6. The valve assemblyaccording to claim 5, wherein said polymer insert device is composed ofone of a natural Polyaryletherketone (PAEK), a filled PAEK and apolyimide material.
 7. The valve assembly according to claim 5, whereinsaid stator face and said rotor face each being composed substantiallyof one a metallic material and a ceramic material, said valve assemblyfurther including: a tribological coating disposed atop at least one ofsaid rotor face and said stator face.
 8. The valve assembly according toclaim 7, wherein said tribological coating is a Diamond Like Carboncoating (DLC).
 9. The valve assembly according to claim 8, wherein saidtribological coating is disposed atop said stator face, and saidreceiving groove is defined in said substantially planar rotor face. 10.The valve assembly according to claim 1, further including: a complianceassembly cooperating with the rotor device in a manner orienting thesubstantially planar rotor face substantially parallel to andsubstantially flush against the substantially planar stator face of thestator device.
 11. A rotary shear valve assembly comprising: a statorboss device defining a substantially hard, substantially planar statorface terminating at an outer circumferential edge, and further definingat least two or more stator channels in fluid communication with saidstator face at corresponding stator ports; a rotor device having asubstantially hard, substantially planar rotor face defining one or morerotor channels, said rotor face extending radially beyond the outercircumferential edge of the stator face when said rotor device isrotatably mounted about a rotational axis to the stator device in amanner enabling fluid-tight, selective relative rotation between therotor face and the stator face, at a rotor-stator interface, between twoor more rotor positions; a tribological coating disposed atop at leastone of said rotor face and said stator face; and a polymer insert devicedefining an exposed contact face having an insert inner diameter lessthan that of said outer circumferential edge and an insert outerdiameter more than said outer circumferential edge, said insert devicebeing formed and dimensioned for press-fit insertion in a receivinggroove defined in said rotor face such that the outer circumferentialedge of said stator face contacts the insert exposed face during saidrelative rotation between said two or more rotor positions.
 12. Thevalve assembly according to claim 11, wherein said insert exposed faceis donut-shaped and substantially planar.
 13. The valve assemblyaccording to claim 12, wherein said receiving groove and said insertdevice cooperate to position the substantially planar insert exposedface substantially flush with the substantially planar rotor face. 14.The valve assembly according to claim 12, wherein a groove innerdiameter of the insert receiving groove is in the range of about 0.001inch to about 0.002 inch greater than that of an insert inner diameterof the insert device.
 15. The valve assembly according to claim 11,wherein said polymer insert device is composed of a high compressivestrength material.
 16. The valve assembly according to claim 15, whereinsaid polymer insert device is composed of one of a natural PAEK, afilled PAEK and a polyimide material.
 17. The valve assembly accordingto claim 11, wherein said stator face and said rotor face each beingcomposed substantially of one a metallic material and a ceramicmaterial.
 18. The valve assembly according to claim 17, wherein saidtribological coating is a Diamond Like Carbon coating (DLC).
 19. Thevalve assembly according to claim 18, wherein said tribological coatingis disposed atop said stator face.
 20. The valve assembly according toclaim 11, further including: a compliance assembly cooperating with therotor device in a manner orienting the substantially planar rotor facesubstantially parallel to and substantially flush against thesubstantially planar stator face of the stator device.